Unipolar dynamo.



No. 861,192. PATENTED' JULY '23. 1907. w. MATHIESEN. UNIPOLAR DYNAMO.

APPLICATION FILED JAN. 25, 1907.

PATBNTED JULY 23, 1907. vW. MATHIESEN.

UNIPOLAR DYNAMO.

APPLICATION FILED JAN.25.1907.

2 SHEETS-SHEET 2.

UNITED STAT ES PATENT OFFICE.

UNIPOLAR DYNAMO.

Specification of Letters Patent.

Patented July 23, 1907.

.Application filed January 25, 1907. Serial No. 354,162.

To all whom it may cof/wem:

Be it known that I, WILHELM MArrnnsnN, manufacturer, a subject of the German Emperor, and residing at Leutzsch-Leipzig, in the Kingdom of Saxony and German Empire, have invented certain new and useful Improvements in and Relating to Unipolar Dynamos, of which the following i's a specification.

For the' purpose of generating electro-motive forces such as are required for ordinary lighting work and power distribution uni-polar dynamos with few armature elements must be run at high speed. The greater the number of revolutions per minute, the fewer arma ture elements and brushes are required for producing any given electro-motive force, and since the efficiency of the machine is largely dependent on the number of brushes used,- it is proportional to the speed at which the machine can'be run.

To avoid injurious effects from unbalanced centrifugal forces in a dynamo run at very high speed, it is, however, essential tc use a shaft or armature7spindle which adjusts itself, with the armature, according to the center of gyration, asis the case with elastic shafts. A shaft possessing elasticity in its entire length between l'rearings, as used for example in the De Laval turbine, has the disadvantage, when used for carrying a` dynamoarmature, that magnetic attraction may drag the armature aside and cause it to adhere to a pole-face. The cntire length of the shaft, or practically the entire length, should therefore be sufficiently rigid to prevent displacement of the armature by magnetic attraction. A wholly elastic shaft has, moreover, the disadvantage that the armature fixed thereto tends to move inte its normal plane of gravitational equilibrium, unless that plane coincides with its geometrical plane, and this may cause the armature to swerve. Such swerving renders it impossible,or at least very difficult, to take current from the armature. The circumferential surfaces of the armature, which must necessarily swerve unless there is-accidental coindence ofthe geometrical plane with the plane of equilibrium, are in that case unavailable for the delivery of current, so that the lateral surfaces must be used for that purpose. faces only run parallel if the freely suspended part of the shaft is inflexible, so the only shaft suitablefor an armature driven at very high speed is one which is capable of oscillating about a fixed center.

Dynamos have been constructed with rigid shafts capableof oscillation, such shafts being journaled at one end ini-bearings which yield to the eccentric movements of the armature For this purpose a movable rbearing has, for example, been used in conjunction with a 4guide-bearing provided with springs, indiarubber cushions or the like. 'A movable bearing of this kind rocks or oscillates inV accordance with the oscillations of the armatue'fand if this takes place, say, 10,000 times per minute the friction 'at` the bearing j renders the latter very hot, so that on the one hand a considerable ,amount of energy is dissipated and on the other' hand the working of the machine is interof the shaft to seek equilibrium.

The oscillation of a non-rotating body, such as a yielding bearing, produces so much friction that only a comparatively low speed is practicable therewith, this being due to the centrifugal forces and the forces which tend to retain the bearing in its normal position. To compensateor balance the oscillations of the armature it has also been proposed to freely suspend the entire machine, so that the field-magnet oscillates with the armature. rlhis arrangement has disadvantages similar to those of yielding bearings. lt has also been proposed to use an elastic shaft in conjunction with a yield ing bearing, but this arrangement is entirely unsuitable for a uni-polar machine with an iron disk-arm ture,` since the shaft is incapable of preventing the swerving of the armature. Moreover the arrangement has the disadvantage that the bearing oscillates and causes energy to he dissipated by friction. These lrnown constructions are not adapted to secure absence of vibration in dynamos run at very high speeds: such absence of vibration can only be secured by using, in conjunction with a disk-armature a shaft adapted to oscillate about a fixed center. Arrangements of this kind are illustrated in the annexeddrawing, in' which Figure l is a section of a uni-polar machine"with a shaft a and means adapting it to oscillate about the center b of the h emi-spherical or universal-joint bearing c, so that the shaft with the armature-parts d, d1, can adjust itself in equilibrium, the cone guide e serving to prevent the'swerving of the free end of the shaft.

Fig. 2 represents a portion of an armature shaft a journaled in a fixed bearing but' having a reduced part or neck, the center b of which is a center of motion. This neck allows of slight deflection of the shaft bui does not permit of the latterl being bent, so that the ar- 4mature cannot be dragged aside by magnetic forces; the resistance opposed by the shaft to these forces increases with the distance between the armature and the neck. With a shaft having a ball-joint 0r fiexible neck it might in some cases occur that the adjustment of the the armatureto swerve, and the play allowedv to the shaft by the guide e might allow thefedge of the arma.- ture to approach and touch the pole-faces at one side. To prevent this, the machines illustrated in the anexed drawing are so constructed that the lateral surfaces of the armature, and the pole-faces adjacent thereto,fform segments of spheres the common center of which is at the center about which the-shaft oscillates. With this construction the `armature disks may swerve considerably at their circumferenceswithput.causing `their lateral surfaces to touch the pole-faces, and confered with by the resistance opposed to the tendency shaft in equilibrium would cause the lateral surfaces of .siderable play may be allowed to the shaft in the guide e without such a Contact taking place. The said spherical surfaces are, moreover, very well adapted for the application of the brushes. If the contact-surfaces of the brushes are flat planes perpendicular to the axis of the shaft, the oscillation of the latter may cause the said surfaces to jar slightly, and this would be injurious with the high speeds used. To overcome the effect of this-jarring it would benecessary to press the brushes down tightly on the armature, but in that case the friction 'would become too great. The sphericalshape of the armature-disks and brush-surfaces is, therefore, of great importance in securing absence of sparking with slight pressure of the brushes. A contact surface which lies approximately in the spherical path of the shaft is also adapted to secure to a greater or less degree the contact-surface may for example be flat and tangential to the sphere, The two armatures d d1 are provided with grooves for the brushes-z z, the contact-surfaces of the said grooves being likewise segments of spheres having their center at the point b. These grooves have the advantage that the radius of friction withv the brushes is small and that the access of oil to the contact surfaces is prevented. If a centrifugal lubricator is usedfoil is liable to be thrown on to the armature and would of course` greatly interfere with the contact of the brushes if the contact-surfaces were external. If, however, the contact-surfaces are in grooves, or within the outer rirn of the armature, the access of oil thereto is prevented, since the armature itself tends to eject the oil by centrifugal force.

Fig. 3 illustrates the arrangement of a vertical shaft with the universal joint c airits lower end, but it is preferable to suspend the shaft from the said joint in View ofV the stable equilibrium secured thereby. Instead of the ball and socket joint and flexible neck illustrated, other arrangements can be used to enable the shaft to oscillate about a fixed center.

In the construction shown in Fig. 4, for example, the shaft o is suspended from a rod g having at each end a ball and socket joint and serving to connect the shaft o.

to the revolving sleeve f. The socket h of the lower Y' to allow of a certain amount of oscillation of the shaft a.

' [n the construction illustrated in Fig. 5 the shaft a has a reduced neck of special length, the upper end of this neck vbeing rigidly fixed to the revoluble sleeve f, and the lower end i being slightly enlarged, with concave circumference, to make contact with the said sleeve, so that the neck allows of a' slight amount of oscillation of the shaft about the center b. Any device equivalent or similar to a universal joint can be used instcad of a ball and socket joint for the purpose indiditcd.

Instead of a single oscillating shaft two such shafts may be used in conjunction, as shown in Fig. 6, one of the said shafts being located 'within the other. The two armature parts d lll are electrically connected to each other and the inner shaft al carries. in addition to thel disk d1, the turliinwwheel k. The shafts oscillate independently about the centers b and b respectively.

seines prevents deflection of the' shaft, but when the latter` has acquired a high speed and has adjusted itself according to the laws. of gyrationthe guide is no longer required, since the elastic member then prevents deflection. 'This construction also has the advantage that it allows of placing the shaft horizontally, which may be of advantage if the dynamo is driven by a steam-turbine. It has been found that the centrifugal forces due to the rapid rotation of the shaft in part convert the oil into a vapor or spray, which passes from the chamber o (Fig. 1) into the chamber p, from which it is sucked by the disk is; this vapor is in part condensed on the walls surrounding the armature, and may saturate the insulation of the magnet coils, and combine with dust to coat and clog the brushes. To obviate these disadvantages, means may be provided for removing the oil spray from the machine by suction or the like. Any suitable suction-device, may be used for this purpose., A pump used for this purpose, directly connected to the oscillating shaft, is shown in Fig. 8, in which the vanes q suck air from the chamber pand force it ,through thechamber o and tube 1' in order to remove the spray. No centrifugal'lubricatbr is shown at the lower part of the shaft, above the guide, but a small 'amount of spray may enter the space s, so that vanes q may be desirable in the latter, to propel air and spray through the tube t.

In the construction shown in Fig. 8 the guide at the hand while the machine is running. For this purpose "the shaft is coned at u, the coned part being located Vwithin an axially movable sleeve or box o. The latter V is `vertically adjustable by means of a hand-lever it, so

that the amount of play allowed to the shaft can be regulated according to the eccentricity of the oscillation and the quantity and' consistency of the oil sup plied. The adjustment of the lever or box may be retained by fitting the box or sleeve o tightly into the part in which it slides, or by any other suitable means. I do not limit myself to' this arrangement for obtaining relative axial movement between the coned part-of the shaft and the box 01 sleeve slu'roundng, it, as any equivalent means may be employed for Ithis purpose.

In v each of the examples so far described, only two armature disks are used, but to generate higher electromotive forces, four or more disks may be' used.

Fig. 9 illustrates `a construction in which four disks are used, eachof the armatures d d consisting of two adjacent disks, one of which has a cylindrical extension intersecting the plane of the other disk, at the circumference. The overlapping circumferential part of one disk, with the insulating material, is interlocked with the circumferential part of the other disk by pressi ingthe disks together, for instance, by means of hydraulic pressure, or by heating the disk with the overlapping cylindrical extension and permitting it to shrink into binding contact with the other diskjion cooling, in order to produce the interlocking effect between the disks. This arrangement. allows of using disks without axial perforation, and the maximum torsion which may be applied to a shaft with disks so united is -nearly as great as the torsion resisted by a single length of shating on which two disks are separateiy keyed.

Fig. 10 illustrates a shaft with two axially perforated doublesrmatures d d1, the latter comprising in the aggregate two outer members and a central member common to both. The armature-parts are assembled by means oi a collar and a nut 9:. The oscillating shaft can be driven from above or below by means of a steamtnrbine and any suitable connecting means. The turbine wheel may, for example, be iixed to a prolongation ot the shaft, as shown in Fig. 8, in which k is the turbine. In this case the turbine has no shait-bearings, but the joint where the shaft enters its casing is made tight by means oi suitable packing, as for exampie at y. l do not limit 'myself to this means o establishing driving connection between the turbine and the dynamo; l may employ any suitable connection which will not defeat the soli-adjusting action oi the-oscillatory armature shaft.

It is obvious that a uni-'polar dynamo constructed lurgical work aswell as for lighting work and power distribution.

`What l claim as my invention and desire to secure by United States Letters Patent is: l

1. A un-po1ar electrical machine comprising a shaft, a universal-joint bearing: through which said shaft is mounted and by which it is permitted to oscillate, a disk armature mounted on said shaft at a point remote from .the universal joint hearing, and magnetic poles adjacent to the armature: the said armature and poles being provided with spherical faces whose plane lies transverse to the shaft whose common center coincides substantially with the center of oscillation of the shaft.

2, A uni-polar electrical machine comprising a shaft, a universal-joint hearing through which said shaft is mounted and hy which it is permitted to oscillate during its rotation, a disk armature mounted on said shaft, and mag- V ol .the armature.

netic poles on opposite sides of the plane of the disk armature, the said armature being provided with spherical suiL faces substantially concentric lwith the center of oscillation of the shaft and the opposed faces of the poles being respectively concave and convex 4to conform to the faces 15. A uni-polar electrical machine comprising a shaft,

means through which said shaft is mounted, constructedto permit said shaft to oscillate about a center, an armature carried by the shaft, and a spherical brush-contact surface having its center lsubstantially coincident with the renter oi' oscillation of the shaft.

Ai. A' uni-polar electrical machine comprising a shaft, and a universal-joint bearing for said shaft; a disl: armature afiixed to said'shaft, and magnetic poles adjacent to said armature; the armature and magnetic poles being formed with spherical faces substantially concentric with the universal-joint hearingnnd with the planes ofthe ser:- ments perpendicular to the shaft, and the universal-joint hearing being located nt a point in the shaft remote from the plane of the armature and permitting the armature to oscillute in a direction transverse io the shaft.

5. A uni-polar electrical machine comprising a shaft, a universal-joint bearing through which said shaft is mounted and 'by which it is permitted to oscillate, a disk arma1 ture carried by said shaft, magnetic poles adjacent to the :ii-mature and a cone bearing adjustable relatively to the shaft; said armature and magnetic poles being formed with spherical faces concentric with the universal-joint hearing, and their planes perpendicular to the shaft, and said universal-joint bearing and adjustable cone hearing being located at points on the shaft remote from and on opposite sides of the disk armature.

(i. A uni-polar electrical machine comprising a shaft, magnetic poles, and a disk armature mountedon the shaft in suitable relation to the magnetic poles; said armature comprising two snperposed but insulated disks, of which one is provided with a circumferential'extension intersecting the plane of the other and fitting tightly upon the periphery of said other disk to interlock the disks together.

The foregoing specification signed at Leipzig, Germany this 29th day of December, 1906.

WILHELM MATHIESEN.

ln presence of- PAUL Haren,

RUDOLPH Fmcnn. 

